It sounded like Isaiah was mentoring Pressey late last season. I think Isaiah can be a good influence as an undersized PG who has learned how to be effective in the NBA. It sounded like Isaiah was teaching him.
So, I'd be interested in giving Pressey another year as 3rd string PG to see if (1) that relationship helps push him forward (2) if he can make inroads with his jump-shooting.
If Pressey does, then he is a keeper beyond next season.
If not, well then it's time to move on from him in summer 2016.